Nacelle Cowl Hinge Latch Mechanism

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Solution Overview

Problem

Aircraft gas turbine engine nacelles face challenges with weight addition and space occupancy due to traditional cowl hinges, which degrade performance and require engine component redesigns.

Innovation Solution

A nacelle design featuring latches configured for threaded engagement with a pin, allowing cowls to rotate and secure in a closed condition, reducing weight and space occupancy by using a combination of latches and rotatable hinges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional gooseneck hinges are used to mount cowls rotatably, then the structural integrity of the nacelle is maintained during flight, but the aircraft weight increases considerably, degrading performance

Engineering Contradiction:
Improvestructural integrityVSAvoidaircraft weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The hinge system is divided into two separate components: a latch mechanism for securing the cowl in the closed position, and a separate rotatable hinge for enabling rotation. This segmentation allows each component to be optimized independently, reducing overall weight while maintaining structural integrity through the latch during flight operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The gooseneck hinge is completely removed from the design. Instead, a simplified latch mechanism is used to secure the cowl, extracting the heavy gooseneck component while maintaining the necessary securing function through alternative means (latch with pin engagement).

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If traditional gooseneck hinges are used to mount cowls rotatably, then the cowls can be secured in closed condition, but the hinges occupy significant space within the engine, requiring engine components to be designed around hinge locations

Engineering Contradiction:
Improvecowl securing capabilityVSAvoidspace occupied by hinge
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

By separating the securing function (latch) from the rotation function (hinge), the design eliminates the need for a large internal gooseneck structure. The latch mechanism occupies minimal space when engaged, and the hinge can be positioned externally or in a more compact configuration, freeing up engine internal space for other component layouts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The latch mechanism uses simple, compact components (latch body, pin, aperture) that occupy minimal space compared to a traditional gooseneck hinge. The pin can be a simple removable fastener rather than a complex integrated hinge structure, reducing the volume required for the securing mechanism.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP3647203B1Nacelle cowl hinge
Publication Date: 2021.08.11 ROHR INC
  • EP3647203B1 patent drawingFigure 1
  • EP3647203B1 patent drawingFigure 2
  • EP3647203B1 patent drawingFigure 3

AI summary

A nacelle (20) for a gas turbine engine (10) includes at least one hinge axis (30) extending along the nacelle (20). At least one cowl (28) is mounted to the nacelle (20), along the at least one hinge axis (30), by a plurality of hinges (34). The plurality of hinges (34) includes at least one latch (36). The at least one latch (36) includes a clevis (40) and a tang (38). The clevis (40) and the tang (38) of the at least one latch (36) are configured to receive a hinge pin (50), through a pin aperture (42), when the at least one cowl (28) is in a closed condition.